IST Lunch Bunch
Classical channel coding theory is concerned with maximizing the
rate of reliable transmission over unreliable channels. Networks such as
the Internet and cellular data networks use packets as the unit of
transmission. While channel coding at the physical layer protects against
symbol-level errors within packets, protection against errors at the level
of packets or links entails coding across packets/links. New issues arise in
the study of this kind of higher layer coding, such as topology and queuing
at the network layer and latency at the application layer, along with
technical challenges such as code length being fixed rather than allowed to
grow. We discuss these issues in the context of packet erasure correction
coding for file transfer and for streaming. We also discuss the issue of
separation between channel coding on individual links and network layer
coding in networks with both symbol-level and network-level errors.